Induction welding employs electromagnetic induction to susceptors for melting plastic parts of plastic pipe distribution systems.
European Patent Publication No. 0 294 008 illustrates and describes an induction weldable socket and a process and apparatus for manufacturing such a socket and a process for connecting the socket to a penetrating pipe part. An induction weldable socket 2 includes an inductively heatable lining 3 near the inner wall of the socket. The socket 2 is manufactured by feeding an inductively heatable lining to a transverse extrusion head of an extruder 21 and cutting the extruded pipe with lining 3 from the extruder to a socket 2. The inductively heating lining 3 may be fed to the extrusion head 22 as a hose 37 assembled or woven from conducting wires or a tube 37 formed from a strip of gauze 34 or an assembly consisting of short-circuited 19a windings obtained by spirally winding a conducting wire.
European Patent Publication No. 0 294 008 FIG. 2 shows an electromagnetic induction coil assembly 10. The electromagnetic induction coil assembly 10 is convenient for placing on an induction weldable socket 2 from above. But the electromagnetic induction coil assembly 10 does not envelope the induction weldable socket 2 from the underside which can lead to weaker welding in comparison to the topside.
Japan Patent Application Publication No. JP 2008111459 illustrates and describes an electromagnetic wave generating apparatus 3 including an electromagnetic mechanism portion 31 for dismountable surrounding a pipe fitting 1 including a series of discrete spaced apart metal rings 11 having a high electric resistance.
PCT International Publication No. WO 2010/033163 illustrates and describes susceptor layers 108 for electromagnetic bond welding of thermoplastic pipe distributions systems and clamp-on electromagnetic coil assemblies for on-site plumbing installations. Susceptor layers 108 are formed from thermoplastic resin in which ferromagnetic particles are embedded.
WO 2010/033163 FIGS. 2A and 2B show an electromagnetic coil assembly including a clamp section 202A enclosing a coil section 206A, a clamp section 202B pivoted to the clamp section and enclosing a coil section 206B, and terminals 208A and 208B respectively connected to coil sections 206A and 206B. WO 2010/0033163 paragraph [0032] describes two fully detachable electromagnetic coil sections with suitable electrical connections for placing around a coupling and then being bolted or clamped together.